1. Field of the Invention
The present invention relates to a method for treating hyperlipidemia or inducing decrease in lipid concentration in the blood which comprises administering a 15-ketoprostaglandin compound to a subject.
The object of the present invention is to induce decrease in concentration of triglyceride, cholesterol or phospholipid in the blood of a patient having an elevated concentration of triglyceride, cholesterol or phospholipid in the blood.
Prostaglandins (hereinafter, prostaglandins are referred to as PGs) are members of a class of organic carboxylic acid that are contained in human and most other mammalian tissues or organs and that exhibit a wide range of physiological activities. Naturally occurring PGs possess as a common structural feature the prostanoic acid skeleton: ##STR1## Some synthetic analogues have somewhat modified skeletons. The primary PGs are classified based on the structural feature of the five-membered cycle moiety into PGAs, PGBs, PGCs, PGDs, PGEs, PGFs, PGGs, PGHs, PGIs and PGJs, and also on the presence or absence of unsaturation and oxidation in the chain moiety as:
______________________________________ Subscript 1 15-OH Subscript 2 5,6-unsaturated-15-OH Subscript 3 5,6- and 17, 18-diunsaturated- 15-OH ______________________________________
Further, PGFs are sub-classified according to the configration of hydroxy group at 9 into .alpha.(hydroxy group being in the alpha configration) and .beta.(hydroxy group being in the beta configration).
2. Background Information
PGE.sub.1, PGE.sub.2 and PGE.sub.3 are known to have vasodilating, hypotensive, gastro-juice reducing, intestine-hyperkinetic, uterine contracting, diuretic, bronchodilating and anti-ulcer activities. Also, PGF.sub.1.alpha., PGF.sub.2.alpha. and PGF.sub.3.alpha. are known to have hypertensive, vasocontracting, intestine-hyperkinetic, uterine contacting, luteo-regressive and bronchocontracting activities.
In addition, some 15-keto (i.e. having an oxo group at position 15 in place of the hydroxy group) prostaglandins and 13,14-dihydro-15-keto-prostaglandins are known as substances naturally produced by enzymatic actions during metabolism of primary PGs (Acta Physiologica Scandinavica, 66, 509, 1966). It has also been described that 15-keto-prostaglandin F.sub.2.alpha. has an antipregnant activity.
European Patent Application No. 0,310,305 describes that 15-keto-PGEs can be used as catharitics. However, it has not been reported that 15-keto-prostaglandin compounds have an activity inducing decrease in concentration of triglyceride, cholesterol or phospholipid in blood.
As a result of extensive studies about the properties of 15-keto-prostaglandin compounds, the present inventors unexpectedly discovered that these compounds have an activity of inducing decrease in concentration of triglyceride, cholesterol or phospholipid in the blood.